As a preface, sometime late last year, I jumped through hoops and hurdles for my 3DS to get my most played games all running online... MHGen, Pokemon OR, FFEX and more, were all doing just that. Then, I got into playing single player games for awhile, and during that time, my router/modem got reset, which means all non-Nintendo devices connected just fine, but... hoops and hurdles. Now, with my router/modem reset, I've gotten back into online gaming, or at least wanting to do so. But I'm constantly bombarded with 006-0612, either an error has occurred or failed to connect to partner's device. That said, what DOES work, is the eShop, Wonder Trading in Pokemon, Spectating in SSB4 annnd, that's about it. What confuses me further, is this router and modem both worked before. I've gone through settings pertaining to the wireless channel, DMZ, wireless signal, security and more, to the point that I spent 2+ hours with a guy from Nintendo customer service, taking remote access control of my laptop, and being thoroughly stumped. All that said, again, late last year I got this all working using, IIRC, a Reddit thread that helped with setting up the right dials, nodes and details of my router, pertaining to Mario Kart 7. And, I enjoyed online gaming on a Nintendo console... such a weird and enjoyable thing. His last bits of advice were it might have to do with my router's firmware version, a newer version being incompatible with my 3DS XL, to try Port Forwarding, which I still don't understand (not looking for a tutorial, but layman's terms as to what that is would be beyond appreciated), and to - fearfully - call my ISP, because they're always helpful. Anyway, I'm on a Belkin N150, latest firmware, with a 3DS XL on Luma3DS/A9HL with 11.4.0-37U. I upgraded to CFW about 4 days ago, but I highly doubt that's the problem. This is a long shot, and I'll probably just get suggestions for doing things I've already done, or to try a different router, but any and all help would be greatly appreciated. EDIT: Did some testing... Games that work include Pokemon Sun Wondertrading, Mario Sports Superstars, SSB4. Games that don't work, Pokemon Sun Battling, FFEX, MHGen, Tri Force Heroes, Mario Kart 7. EDIT: Forwarded 8 different ports, I can now battle in Pokemon Sun, and play Tri Force Heroes (albeit in a lobby, with only 1 other person, at 10FPS). Sadly, all other non-working games, still non-work. I also power cycled both modem and router, to no avail. I believe (I'm about 95% on this), I have all settings back on my router that were once there that allowed all my online games, except Animal Crossing (because New Leaf was always a kick in the balls getting online), playable online. Except 2 changes... one, its on the latest firmware. I never had it on the latest firmware before and ignored any updates (was on ver.4, now its on ver.5), and B., my internet plan is faster than it once was. So, I'm hoping downgrading the router's firmware will fix it. If not, I have no clue... it's like coming home, using your key to open your front door and going in, then a day later, doing the same and the same exact key doesn't fit the lock.